1. Field of the Invention
The present invention relates to a light emitting device, a display apparatus having the light emitting device, and a method of manufacturing the display apparatus. More particularly, the present invention relates to a light emitting device having a reduced volume and an improved durability, a display apparatus including the light emitting device, and a method of manufacturing the display apparatus.
2. Description of the Related Art
Recently, information processing apparatuses becomes more important and the information processing apparatuses are widely used in various fields of several industries. However, because processed data by the information processing apparatus are generally represented as electric signals or codes, users may not directly identify the processed data with naked eyes. Thus, a display apparatus serving as an interface is required for user to identify the processed data by the information processing apparatus.
The display apparatuses are generally classified into emissive display apparatuses and non-emissive display apparatuses. The emissive display apparatus typically includes a cathode ray tube (CRT), a plasma display panel (PDP), a light emitting diode (LED), an electro-luminescence display (ELD) device, etc. The non-emissive display apparatus typically includes a liquid crystal display (LCD) device, an electrochemical display (ECD), an electro-phoretic image display (EPID), etc.
In the emissive display apparatus, the ELD devices become important. The ELD devices are typically divided into inorganic electro-luminescence display devices and organic electro-luminescence display devices according as electro-luminescence materials thereof.
The organic electro-luminescence display device has an anode electrode and a cathode electrode, and an organic light emitting layer. The organic light emitting layer has characteristics deteriorated by oxygen or moisture permeated into the organic light emitting layer because the organic light emitting layer is composed of organic material. When the organic light emitting layer contacts with oxygen or moisture in air, the lifetime of the organic light emitting layer may be rapidly reduced.
Table I shows the luminescence of the light generated from a conventional organic electro-luminescence display device. In Table 1, the organic electro-luminescence display device is exposed to an inferior environment in which the content of moisture is about 80%, temperature is about 80° C. and applied current is about 20 mA/cm2. The lifetime of the organic electro-luminescence display device corresponds to the time when the luminance of the light generated from the organic electro-luminescence display device becomes a half of an initial luminance thereof.
time (hour)luminescence (%)01005811075.515712067256430603557405343.650
As shown in Table 1, the luminance of the light generated from the organic electro-luminescence display device rapidly decreases in proportion as time elapses. After about 43 hours, the luminance of the light generated from the organic electro-luminescence display device decreases to half of an initial luminance thereof. That is, the organic electro-luminescence display device may have a lifetime of about 43 hours when the organic electro-luminescence display device rapidly makes contact with moisture or oxygen in air.
Considering this problem, there is provides an organic electro-luminescence display device including a metal cap that prevents moisture or oxygen from directly contacting the organic electro-luminescence display device. However, moisture or oxygen may gradually permeate into the organic electro-luminescence display device through a gap between the metal cap and the organic electro-luminescence display device when the organic electro-luminescence display device is covered with the metal cap. Therefore, the electrical characteristics and lifetime of the organic electro-luminescence display device may be gradually deteriorated by the permeated oxygen or moisture. Further, the organic electro-luminescence display device may have increased volume and weigh when the organic electro-luminescence display device has the metal cap.